Intraoperative myocardial contrast echocardiography for assessment of regional bypass perfusion

The intraoperative determination of the success of surgical myocardial revascularization remains problematic because of major limitations in all currently used methods. To assess the regional blood flow of the bypass graft-dependent myocardial segments, 2 ml of sonicated iopromid (a nonionic x-ray contrast medium) was injected into the bypass graft in the beating heart. Simultaneously electromagnetic flow measurements were performed. Eleven graft injections in 8 men (mean age +/- standard deviation 60 +/- 4 years) were performed without any adverse effects. Excellent 2-dimensional cross-sectional views of the left ventricle were obtained in all cases. Ten of 11 injections resulted in adequate myocardial opacification. Computer-assisted evaluation by videodensitometry resulted in time-intensity curves with contrast decay half-times (T1/2) from 2.2 to 6.9 seconds (mean 4.3 +/- 1.4). The corresponding electromagnetic flow ranged from 55 to 100 ml/min (mean 80.0 +/- 16.2). there was no correlation between contrast 2-dimensional echocardiography-derived T1/2 and electromagnetic flow (r = 0.32; p = 0.38). Thus, myocardial contrast echocardiography is a feasible and safe method for intraoperative evaluation of the success of bypass graft surgery. It offers online visualization of perfusion of revascularized myocardium and may allow immediate intraoperative revision of unsuccessful bypass graft placement.